Is it possible to set BLE and FDS's interrupt priorities separately?

[RJ Fang]

Hi everyone,

Hope you are doing well!

I am using BLE and FDS simutinuously but since they share the same interrupt priority (SD_EVT_IRQn = 4), fds events will be blocked if they are triggered within ble interrupts.

One way to solve this issure is to call fds write and erase functions in main loop and set flags in ble interrupts but specifically, that will complex my project so I am wondering if there's a way to set BLE and FDS's interrupt priorities separately?

Thanks for your help in advance!

Best regards,

RJ

[Susheel Nuguru]

Hi Fang,

FDS uses fstorage.

Inside nrf_fstorage_sd.c you can see that it uses SDH observer priority of 0.

NRF_SDH_SOC_OBSERVER(m_sys_obs, 0, nrf_fstorage_sys_evt_handler, NULL);

and in the SDK config you can see that NRF_SDH_SOC_STACK_OBSERVER_PRIO is also set to 0. These are software priorities based on the same interrupt line SWI2_IRQn that are used by softdevice to notify both BLE/ANT and also fstorage events.

These events are queued inside softdevice and these software priorities only define the order in which the handlers for these events are called. In your case, the BLE events and Fstorage events are of same priority, so if BLE events comes first in the queue they are processed first and if fstorage events comes first in the queue, they are processed first delaying the BLE event processing. If you want to change this behavior, you need to change the priorities of these as to how you want priority preference between BLE and fstorage events.

[RJ Fang]

Hi Susheel,

Thanks for your reply! Could you please specify what should I do if I want to set FDS's interrupt priority higher then BLE's priority?

[Susheel Nuguru]

change NRF_SDH_SOC_STACK_OBSERVER_PRIO from 0 to 1 if you think that fstorage events should be pulled first from the item queue even if ble event arrived first.

[RJ Fang]

I have tried that but it didn't solve my issue. So specifically I am trying to call fds_write inside a ble interrupt handler:

on_write(data from ble)

{

    fds_write(data from ble);

}

The on_write() function is the handler for ble writing event. If I chagned the priority like you said, will this function working theoretically?

[Susheel Nuguru]

what you are trying to do in the pseudocode and the main discussion of the thread seems to have diverged.

I thought that the discussion of this thread is about priorities in how BLE and FDS events are handled and not the priority of new FDS procedure request.